The present invention relates to digital printing and, more particularly, to a reusable digital printing plate for recess and/or relief printing.
Nowadays, it is common to use digital and computerized means to draw and transfer the data to be impressed, either directly to the printing machine, or via certain pre-press preparations, thereby facilitating also the printing make-ready process. Low-end printing applications generally use small digital printers based on impact (usually dot matrix), ink jet or laser printing techniques. The printing quality varies then from plain to high-quality printing, wherein the digital information sent directly to the printing mechanism enables fast on-line modifications of the printing layout.
Middle range applications usually use commercial printers for fast printing and high quality of medium quantities (thousands) of printouts of a wide range of products such as announcements, brochures, posters, booklets, fliers, stationery, business forms, books and magazines.
Generally, the size of the printing machines intended to be used in service bureaus is less important. These machines use sophisticated methods of printing based on transfer of an entire film of colored ink to the paper at each cycle, utilizing digital means for drawing production and data transfer.
In recently announced printing machines, fast updating of the reproductions is possible. Although the change of the appearance of consecutive printouts is generally not crucial, personalized printouts can be done, based on the digital capabilities of the printing machine. The TurboStream system made by Indigo is an example of a sheet-fed digital printing device, with the option of full-color personalization of text, graphics and images.
For high-end applications, such as journals, newspapers, etc., very high volumes of printing (over tens of thousands) are necessary. Generally, media for high quality printouts are required. The same output is repeated many times, and personalized printings are rare. Existing printing systems use printing plates of various materials, such as metal (usually aluminum), paper, rubber or plastic, carrying an image to be reproduced using a printer press. The structure of the printing plates depends on the printing process. For example, recess (intaglio) printings, like gravure, rotogravure using a web press, and engraving, use printing plates with different levels for inked areas and non-inked areas, having inked areas recessed related to the non-inked areas; whereas relief printings, like letterpress, block printing and flexography, also use printing plates with different levels for inked areas and non-inked areas, but in this case the inked areas protrude over the non-inked areas.
Another common printing method is lithography, using plates whose image areas attract ink and whose non-image areas repel ink. However, existing printing plates are difficult to reuse and personalize, and their storage, especially for the case of metal plates for printing large size paper sheets, is space consuming. Furthermore, plate making is usually time-consuming and cumbersome, though advanced techniques of computer-to-plate (CTP) somewhat facilitate this process.
There is thus a widely recognized need for, and it would be highly advantageous to have, a reusable digital printing plate, for middle range to high-end applications, that is simple and straightforward to manufacture, operate and use.